With the 2.39 firmware release, the RetroTink-5X Pro video scaler gained the ability to save up to 10 profiles with customized settings, making it easy to switch between commonly used configurations. However, these profiles do not persist after a firmware update so I've catalogued mine here in case I need to refer to them later, as well as a brief explanation of what I use each one for.
I prefer to use 1080p (Over) as my default output resolution to get a clean integer scale at my display's native resolution. So far, I have run into very few cases where something is cut off in the overscan, and it is trivial to fix if that happens, so I just roll with it.
I use slots 1-5 for my profiles when playing normally, and I store parallel versions of these profiles into slots 6-10 with scanlines disabled for streaming/capture purposes. Scanlines tend to look very bad when displayed at anything other than the native resolution.
Any settings that are not explicitly listed below retain their default values.
I use this profile to play PS1 and Saturn games over RGB/SCART with the scanline preset I enjoy.
I use this profile to play PS2 and Wii games over Component with the scanline preset I enjoy when they don't support widescreen, or if the widescreen mode looks bad compared to 4:3.
I use this profile to play PS2 and Wii games over Component when they support widescreen output. I prefer playing widescreen games without scanline effects enabled. The horizontal crop strips out a green stripe at the very left of the display when playing PS2 games, which may be particular to my setup.